libxl: add a flag to mark guests as tainted by a hook

The migrate hook will affect the migrated guest definition. Allow
these domains be marked as tainted in the libxl driver.

src/libxl/libxl_domain.c

@@ -1135,6 +1135,16 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
                                        vm->def, hostdev_flags) < 0)
         goto cleanup_dom;
 
+    if (priv->hookRun) {
+        char uuidstr[VIR_UUID_STRING_BUFLEN];
+        virUUIDFormat(vm->def->uuid, uuidstr);
+
+        VIR_WARN("Domain id='%d' name='%s' uuid='%s' is tainted: hook",
+                 vm->def->id,
+                 vm->def->name,
+                 uuidstr);
+    }
+
     /* Unlock virDomainObj while creating the domain */
     virObjectUnlock(vm);
 

src/libxl/libxl_domain.h

@@ -69,6 +69,8 @@ struct _libxlDomainObjPrivate {
     char *lockState;
 
     struct libxlDomainJobObj job;
+
+    bool hookRun;  /* true if there was a hook run over this domain */
 };